9.触摸屏驱动（IIC）移植实战
转自 https://edu.csdn.net/lecturer/505 朱老师物联网大讲堂《5.linux驱动开发-第9部分-5.9.触摸屏驱动移植实战》第一部分、章节目录5.9.1.触摸屏驱动概览5.9.2.内核中的竞争状态和互斥15.9.3.内核中的竞争状态和互斥25.9.4.中断的上下半部15.9.5.中断的上下半部25.9.6.linux内核的I2C子系统详解15.9.7.linux内核
·
9.1.触摸屏驱动概览
9.1.1、常用的2种触摸屏
(1)电阻触摸屏。驱动一般分2种：一种是SoC内置触摸屏控制器，一种是外置的专门触摸屏控制芯片，通过I2C接口和SoC通信。
(2)电容触摸屏。驱动只有一种，外接专用的电容式触摸屏控制芯片，I2C接口和SoC通信。
9.1.2、学习触摸屏驱动的关键点
(1)input子系统相关知识
(2)中断上下半部
(3)I2C子系统
(4)触摸屏芯片本身知识
9.1.3、竞争状态和同步
9.2_3.内核中的竞争状态和互斥
9.2.1、一些概念
(1)竞争状态（简称竟态）
(2)临界段、互斥锁、死锁
(3)同步（多CPU、多任务、中断）
9.2.2、解决竟态的方法
(1)原子操作 automic_t
(2)信号量、互斥锁
(3)自旋锁
9.2.3、自旋锁和信号量的使用要点
(1)自旋锁不能递归
(2)自旋锁可以用在中断上下文（信号量不可以，因为可能睡眠），但是在中断上下文中获取自旋锁之前要先禁用本地中断
(3)自旋锁的核心要求是：拥有自旋锁的代码必须不能睡眠，要一直持有CPU直到释放自旋锁
(4)信号量和读写信号量适合于保持时间较长的情况，它们会导致调用者睡眠，因此只能在进程上下文使用，而自旋锁适合于保持时间非常短的情况，它可以在任何上下文使用。如果被保护的共享资源只在进程上下文访问，使用信号量保护该共享资源非常合适，如果对共享资源的访问时间非常短，自旋锁也可以。但是如果被保护的共享资源需要在中断上下文访问（包括底半部即中断处理句柄和顶半部即软中断），就必须使用自旋锁。自旋锁保持期间是抢占失效的，而信号量和读写信号量保持期间是可以被抢占的。自旋锁只有在内核可抢占或SMP（多处理器）的情况下才真正需要，在单CPU且不可抢占的内核下，自旋锁的所有操作都是空操作。
9.4.中断的上下半部1
9.4.1、中断处理的注意点
(1)中断上下文，不能和用户空间数据交互
(2)不能交出CPU（不能休眠、不能schedule）
(3)ISR运行时间尽可能短，越长则系统响应特性越差
9.4.2、中断下半部2种解决方案
(1)为什么要分上半部（top half，又叫顶半部）和下半部（bottom half，又叫底半部）
(2)下半部处理策略1：tasklet（小任务）
(3)下半部处理策略2：workqueue（工作队列）
9.4.3、tasklet使用实战
(1)tasklet相关接口介绍
(2)实战演示tasklet实现下半部
#include <linux/input.h>
#include <linux/module.h>
#include <linux/init.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <mach/irqs.h> // arch/arm/mach-s5pv210/include/mach/irqs.h
#include <linux/interrupt.h>
#include <linux/gpio.h>
/*
* X210:
*
* POWER -> EINT1 -> GPH0_1
* LEFT -> EINT2 -> GPH0_2
* DOWN -> EINT3 -> GPH0_3
* UP -> KP_COL0 -> GPH2_0
* RIGHT -> KP_COL1 -> GPH2_1
* MENU -> KP_COL3 -> GPH2_3 (KEY_A)
* BACK -> KP_COL2 -> GPH2_2 (KEY_B)
*/
#define BUTTON_IRQ IRQ_EINT2
static struct input_dev *button_dev;
// 下半部函数
void func(unsigned long data)
{
int flag;
printk("key-s5pv210: this is bottom half\n");
s3c_gpio_cfgpin(S5PV210_GPH0(2), S3C_GPIO_SFN(0x0)); // input模式
flag = gpio_get_value(S5PV210_GPH0(2));
s3c_gpio_cfgpin(S5PV210_GPH0(2), S3C_GPIO_SFN(0x0f)); // eint2模式
input_report_key(button_dev, KEY_LEFT, !flag);
input_sync(button_dev);
}
DECLARE_TASKLET(mytasklet, func, 0);
static irqreturn_t button_interrupt(int irq, void *dummy)
{
printk("key-s5pv210: this is top half\n");
tasklet_schedule(&mytasklet);
return IRQ_HANDLED;
}
static int __init button_init(void)
{
int error;
error = gpio_request(S5PV210_GPH0(2), "GPH0_2");
if(error)
printk("key-s5pv210: request gpio GPH0(2) fail");
s3c_gpio_cfgpin(S5PV210_GPH0(2), S3C_GPIO_SFN(0x0f)); // eint2模式
if (request_irq(BUTTON_IRQ, button_interrupt, IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING, "button-x210", NULL))
{
printk(KERN_ERR "key-s5pv210.c: Can't allocate irq %d\n", BUTTON_IRQ);
return -EBUSY;
}
button_dev = input_allocate_device();
if (!button_dev)
{
printk(KERN_ERR "key-s5pv210.c: Not enough memory\n");
error = -ENOMEM;
goto err_free_irq;
}
button_dev->evbit[0] = BIT_MASK(EV_KEY);
button_dev->keybit[BIT_WORD(KEY_LEFT)] = BIT_MASK(KEY_LEFT);
error = input_register_device(button_dev);
if (error)
{
printk(KERN_ERR "key-s5pv210.c: Failed to register device\n");
goto err_free_dev;
}
return 0;
err_free_dev:
input_free_device(button_dev);
err_free_irq:
free_irq(BUTTON_IRQ, button_interrupt);
return error;
}
static void __exit button_exit(void)
{
input_unregister_device(button_dev);
free_irq(BUTTON_IRQ, button_interrupt);
}
module_init(button_init);
module_exit(button_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("aston <1264671872@qq.com>");
MODULE_DESCRIPTION("key driver for x210 button.");
9.5.中断的上下半部2
9.5.1、workqueue实战演示
(1)workqueue的突出特点是下半部会交给worker thead，因此下半部处于进程上下文，可以被调度，因此可以睡眠。
(2)include/linux/workqueue.h
9.5.2、中断上下半部处理原则
(1)必须立即进行紧急处理的极少量任务放入在中断的顶半部中，此时屏蔽了与自己同类型的中断，由于任务量少，所以可以迅速不受打扰地处理完紧急任务。
(2)需要较少时间的中等数量的急迫任务放在tasklet中。此时不会屏蔽任何中断（包括与自己的顶半部同类型的中断），所以不影响顶半部对紧急事务的处理；同时又不会进行用户进程调度，从而保证了自己急迫任务得以迅速完成。
(3)需要较多时间且并不急迫（允许被操作系统剥夺运行权）的大量任务放在workqueue中。此时操作系统会尽量快速处理完这个任务，但如果任务量太大，期间操作系统也会有机会调度别的用户进程运行，从而保证不会因为这个任务需要运行时间将其它用户进程无法进行。
(4)可能引起睡眠的任务放在workqueue中。因为在workqueue中睡眠是安全的。在需要获得大量的内存时、在需要获取信号量时，在需要执行阻塞式的I/O操作时，用workqueue很合适。
#include <linux/input.h>
#include <linux/module.h>
#include <linux/init.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <mach/irqs.h> // arch/arm/mach-s5pv210/include/mach/irqs.h
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <linux/workqueue.h>
/*
* X210:
*
* POWER -> EINT1 -> GPH0_1
* LEFT -> EINT2 -> GPH0_2
* DOWN -> EINT3 -> GPH0_3
* UP -> KP_COL0 -> GPH2_0
* RIGHT -> KP_COL1 -> GPH2_1
* MENU -> KP_COL3 -> GPH2_3 (KEY_A)
* BACK -> KP_COL2 -> GPH2_2 (KEY_B)
*/
#define BUTTON_IRQ IRQ_EINT2
static struct input_dev *button_dev;
// 下半部函数
void func(struct work_struct *work)
{
int flag;
printk("key-s5pv210: this is workqueue bottom half\n");
s3c_gpio_cfgpin(S5PV210_GPH0(2), S3C_GPIO_SFN(0x0)); // input模式
flag = gpio_get_value(S5PV210_GPH0(2));
s3c_gpio_cfgpin(S5PV210_GPH0(2), S3C_GPIO_SFN(0x0f)); // eint2模式
input_report_key(button_dev, KEY_LEFT, !flag);
input_sync(button_dev);
}
DECLARE_WORK(mywork, func);
static irqreturn_t button_interrupt(int irq, void *dummy)
{
printk("key-s5pv210: this is workqueue top half\n");
schedule_work(&mywork);
return IRQ_HANDLED;
}
static int __init button_init(void)
{
int error;
error = gpio_request(S5PV210_GPH0(2), "GPH0_2");
if(error)
printk("key-s5pv210: request gpio GPH0(2) fail");
s3c_gpio_cfgpin(S5PV210_GPH0(2), S3C_GPIO_SFN(0x0f)); // eint2模式
if (request_irq(BUTTON_IRQ, button_interrupt, IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING, "button-x210", NULL))
{
printk(KERN_ERR "key-s5pv210.c: Can't allocate irq %d\n", BUTTON_IRQ);
return -EBUSY;
}
button_dev = input_allocate_device();
if (!button_dev)
{
printk(KERN_ERR "key-s5pv210.c: Not enough memory\n");
error = -ENOMEM;
goto err_free_irq;
}
button_dev->evbit[0] = BIT_MASK(EV_KEY);
button_dev->keybit[BIT_WORD(KEY_LEFT)] = BIT_MASK(KEY_LEFT);
error = input_register_device(button_dev);
if (error)
{
printk(KERN_ERR "key-s5pv210.c: Failed to register device\n");
goto err_free_dev;
}
return 0;
err_free_dev:
input_free_device(button_dev);
err_free_irq:
free_irq(BUTTON_IRQ, button_interrupt);
return error;
}
static void __exit button_exit(void)
{
input_unregister_device(button_dev);
free_irq(BUTTON_IRQ, button_interrupt);
}
module_init(button_init);
module_exit(button_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("aston <1264671872@qq.com>");
MODULE_DESCRIPTION("key driver for x210 button.");
9.6 linux内核的I2C子系统详解
9.6.1、I2C总线汇总概览
(1)三根通信线：SCL、SDA、GND
(2)同步、串行、电平、低速、近距离
(3)总线式结构，支持多个设备挂接在同一条总线上
(4)主从式结构，通信双方必须一个为主（master）一个为从（slave），主设备掌握每次通信的主动权，从设备按照主设备的节奏被动响应。每个从设备在总线中有唯一的地址（slave address），主设备通过从地址找到自己要通信的从设备（本质是广播）。
(5)I2C主要用途就是主SoC和外围设备之间的通信，最大优势是可以在总线上扩展多个外围设备的支持。常见的各种物联网传感器芯片（如gsensor、温度、湿度、光强度、酸碱度、烟雾浓度、压力等）均使用I2C接口和主SoC进行连接。
(6)电容触摸屏芯片的多个引脚构成2个接口。一个接口是I2C的，负责和主SoC连接（本身作为从设备），主SoC通过该接口初始化及控制电容触摸屏芯片、芯片通过该接口向SoC汇报触摸事件的信息（触摸坐标等），我们使用电容触摸屏时重点关注的是这个接口；另一个接口是电容触摸板的管理接口，电容触摸屏芯片通过该接口来控制触摸板硬件。该接口是电容触摸屏公司关心的，他们的触摸屏芯片内部固件编程要处理这部分，我们使用电容触摸屏的人并不关心这里。
9.6.2、linux内核的I2C驱动框架总览
(1)I2C驱动框架的主要目标是：让驱动开发者可以在内核中方便的添加自己的I2C设备的驱动程序，从而可以更容易的在linux下驱动自己的I2C接口硬件
(2)源码中I2C相关的驱动均位于：drivers/i2c目录下。linux系统提供2种I2C驱动实现方法：第一种叫i2c-dev，对应drivers/i2c/i2c-dev.c，这种方法只是封装了主机（I2C master，一般是SoC中内置的I2C控制器）的I2C基本操作，并且向应用层提供相应的操作接口，应用层代码需要自己去实现对slave的控制和操作，所以这种I2C驱动相当于只是提供给应用层可以访问slave硬件设备的接口，本身并未对硬件做任何操作，应用需要实现对硬件的操作，因此写应用的人必须对硬件非常了解，其实相当于传统的驱动中干的活儿丢给应用去做了，所以这种I2C驱动又叫做“应用层驱动”，这种方式并不主流，它的优势是把差异化都放在应用中，这样在设备比较难缠（尤其是slave是非标准I2C时）时不用动驱动，而只需要修改应用就可以实现对各种设备的驱动。这种驱动在驱动层很简单（就是i2c-dev.c）我们就不分析了。
(3)第二种I2C驱动是所有的代码都放在驱动层实现，直接向应用层提供最终结果。应用层甚至不需要知道这里面有I2C存在，譬如电容式触摸屏驱动，直接向应用层提供/dev/input/event1的操作接口，应用层编程的人根本不知道event1中涉及到了I2C。这种是我们后续分析的重点。
9.8.linux内核的I2C子系统详解3
9.8.1、I2C子系统的4个关键结构体
(1)struct i2c_adapter I2C适配器
(2)struct i2c_algorithm I2C算法
(3)struct i2c_client I2C（从机）设备信息
(4)struct i2c_driver I2C（从机）设备驱动
9.8.2、关键文件
(1)\drivers\i2c\i2c-core.c
(2)\drivers\i2c\busses目录
(3)\drivers\i2c\algos目录
9.9.linux内核的I2C子系统详解4
9.9.1、i2c-core.c初步分析
(1)smbus代码略过
(2)模块加载和卸载:bus_register(&i2c_bus_type);
9.9.2、I2C总线的匹配机制
(1)match函数
(2)probe函数
总结：I2C总线上有2条分支：i2c_client链和i2c_driver链，当任何一个driver或者client去注册时，I2C总线都会调用match函数去对client.name和driver.id_table.name进行循环匹配。如果driver.id_table中所有的id都匹配不上则说明client并没有找到一个对应的driver，没了；如果匹配上了则标明client和driver是适用的，那么I2C总线会调用自身的probe函数，自身的probe函数又会调用driver中提供的probe函数，driver中的probe函数会对设备进行硬件初始化和后续工作。
9.9.3、核心层开放给其他部分的注册接口
(1)i2c_add_adapter/i2c_add_numbered_adapter 注册adapter的
(2)i2c_add_driver 注册driver的
(3)i2c_new_device 注册client的
9.10.linux内核的I2C子系统详解5
9.10.1、adapter模块的注册
(1)平台总线方式注册
(2)找到driver和device，并且确认其配对过程
(3)probe函数
9.10.2、probe函数分析
(1)填充一个i2c_adapter结构体，并且调用接口去注册之
(2)从platform_device接收硬件信息，做必要的处理（request_mem_region & ioremap、request_irq等）
(3)对硬件做初始化（直接操作210内部I2C控制器的寄存器）
9.10.3、i2c_algorithm
(1)i2c->adap.algo = &s3c24xx_i2c_algorithm;
(2)functionality
(3)s3c24xx_i2c_doxfer
9.11_12.linux内核的I2C子系统详解6_7
9.11.1、i2c_driver的注册
(1)以gslX680的驱动为例
(2)将驱动添加到内核SI项目中
(3)i2c_driver的基本分析：name和probe
9.11.2、i2c_client从哪里来
(1)直接来源：i2c_register_board_info
smdkc110_machine_init
i2c_register_board_info
struct i2c_board_info {
char type[I2C_NAME_SIZE]; // 设备名
unsigned short flags; // 属性
unsigned short addr; // 设备从地址
void *platform_data; // 设备私有数据
struct dev_archdata *archdata;
#ifdef CONFIG_OF
struct device_node *of_node;
#endif
int irq; // 设备使用的IRQ号，对应CPU的EINT
};
(2)实现原理分析
内核维护一个链表 __i2c_board_list，这个链表上链接的是I2C总线上挂接的所有硬件设备的信息结构体。也就是说这个链表维护的是一个struct i2c_board_info结构体链表。
真正的需要的struct i2c_client在别的地方由__i2c_board_list链表中的各个节点内容来另外构建生成。
函数调用层次：
i2c_add_adapter/i2c_add_numbered_adapter
i2c_register_adapter
i2c_scan_static_board_info
i2c_new_device
device_register
总结：I2C总线的i2c_client的提供是内核通过i2c_add_adapter/i2c_add_numbered_adapter接口调用时自动生成的，生成的原料是mach-x210.c中的i2c_register_board_info(1, i2c_devs1, ARRAY_SIZE(i2c_devs1));
9.13. goodix驱动的移植实践
源码目录：\input\touchscreen\goodix.c
完整代码：
/*
* Driver for Goodix Touchscreens
*
* Copyright (c) 2014 Red Hat Inc.
* Copyright (c) 2015 K. Merker <merker@debian.org>
*
* This code is based on gt9xx.c authored by andrew@goodix.com:
*
* 2010 - 2012 Goodix Technology.
*/
/*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; version 2 of the License.
*/
#include <linux/kernel.h>
#include <linux/dmi.h>
#include <linux/firmware.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/input/mt.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include <linux/of.h>
#include <asm/unaligned.h>
#include "../../gpio/gpiolib.h"
struct goodix_ts_data {
struct i2c_client *client;
struct input_dev *input_dev;
int abs_x_max;
int abs_y_max;
bool swapped_x_y;
bool inverted_x;
bool inverted_y;
unsigned int max_touch_num;
unsigned int int_trigger_type;
int cfg_len;
struct gpio_desc *gpiod_int;
struct gpio_desc *gpiod_rst;
u16 id;
u16 version;
const char *cfg_name;
struct completion firmware_loading_complete;
unsigned long irq_flags;
};
#define GOODIX_GPIO_INT_NAME "irq"
//#define GOODIX_GPIO_RST_NAME "reset"
#define GOODIX_GPIO_RST_NAME "rst"
#define GOODIX_MAX_HEIGHT 854
#define GOODIX_MAX_WIDTH 480
#define GOODIX_INT_TRIGGER 1
#define GOODIX_CONTACT_SIZE 8
#define GOODIX_MAX_CONTACTS 10
#define GOODIX_CONFIG_MAX_LENGTH 240
#define GOODIX_CONFIG_911_LENGTH 186
#define GOODIX_CONFIG_967_LENGTH 228
/* Register defines */
#define GOODIX_REG_COMMAND 0x8040
#define GOODIX_CMD_SCREEN_OFF 0x05
#define GOODIX_READ_COOR_ADDR 0x814E
#define GOODIX_REG_CONFIG_DATA 0x8047
#define GOODIX_REG_ID 0x8140
#define GOODIX_BUFFER_STATUS_READY BIT(7)
#define GOODIX_BUFFER_STATUS_TIMEOUT 20
#define RESOLUTION_LOC 1
#define MAX_CONTACTS_LOC 5
#define TRIGGER_LOC 6
static const unsigned long goodix_irq_flags[] = {
IRQ_TYPE_EDGE_RISING,
IRQ_TYPE_EDGE_FALLING,
IRQ_TYPE_LEVEL_LOW,
IRQ_TYPE_LEVEL_HIGH,
};
/*
* Those tablets have their coordinates origin at the bottom right
* of the tablet, as if rotated 180 degrees
*/
static const struct dmi_system_id rotated_screen[] = {
#if defined(CONFIG_DMI) && defined(CONFIG_X86)
{
.ident = "WinBook TW100",
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "WinBook"),
DMI_MATCH(DMI_PRODUCT_NAME, "TW100")
}
},
{
.ident = "WinBook TW700",
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "WinBook"),
DMI_MATCH(DMI_PRODUCT_NAME, "TW700")
},
},
#endif
{}
};
/**
* goodix_i2c_read - read data from a register of the i2c slave device.
*
* @client: i2c device.
* @reg: the register to read from.
* @buf: raw write data buffer.
* @len: length of the buffer to write
*/
static int goodix_i2c_read(struct i2c_client *client,
u16 reg, u8 *buf, int len)
{
struct i2c_msg msgs[2];
u16 wbuf = cpu_to_be16(reg);
int ret;
msgs[0].flags = 0;
msgs[0].addr = client->addr;
msgs[0].len = 2;
msgs[0].buf = (u8 *)&wbuf;
msgs[1].flags = I2C_M_RD;
msgs[1].addr = client->addr;
msgs[1].len = len;
msgs[1].buf = buf;
ret = i2c_transfer(client->adapter, msgs, 2);
return ret < 0 ? ret : (ret != ARRAY_SIZE(msgs) ? -EIO : 0);
}
/**
* goodix_i2c_write - write data to a register of the i2c slave device.
*
* @client: i2c device.
* @reg: the register to write to.
* @buf: raw data buffer to write.
* @len: length of the buffer to write
*/
static int goodix_i2c_write(struct i2c_client *client, u16 reg, const u8 *buf,
unsigned len)
{
u8 *addr_buf;
struct i2c_msg msg;
int ret;
addr_buf = kmalloc(len + 2, GFP_KERNEL);
if (!addr_buf)
return -ENOMEM;
addr_buf[0] = reg >> 8;
addr_buf[1] = reg & 0xFF;
memcpy(&addr_buf[2], buf, len);
msg.flags = 0;
msg.addr = client->addr;
msg.buf = addr_buf;
msg.len = len + 2;
ret = i2c_transfer(client->adapter, &msg, 1);
kfree(addr_buf);
return ret < 0 ? ret : (ret != 1 ? -EIO : 0);
}
static int goodix_i2c_write_u8(struct i2c_client *client, u16 reg, u8 value)
{
return goodix_i2c_write(client, reg, &value, sizeof(value));
}
static int goodix_get_cfg_len(u16 id)
{
switch (id) {
case 911:
case 9271:
case 9110:
case 927:
case 928:
return GOODIX_CONFIG_911_LENGTH;
case 912:
case 967:
return GOODIX_CONFIG_967_LENGTH;
default:
return GOODIX_CONFIG_MAX_LENGTH;
}
}
static int goodix_ts_read_input_report(struct goodix_ts_data *ts, u8 *data)
{
unsigned long max_timeout;
int touch_num;
int error;
/*
* The 'buffer status' bit, which indicates that the data is valid, is
* not set as soon as the interrupt is raised, but slightly after.
* This takes around 10 ms to happen, so we poll for 20 ms.
*/
max_timeout = jiffies + msecs_to_jiffies(GOODIX_BUFFER_STATUS_TIMEOUT);
do {
error = goodix_i2c_read(ts->client, GOODIX_READ_COOR_ADDR,
data, GOODIX_CONTACT_SIZE + 1);
if (error) {
dev_err(&ts->client->dev, "I2C transfer error: %d\n",
error);
return error;
}
if (data[0] & GOODIX_BUFFER_STATUS_READY) {
touch_num = data[0] & 0x0f;
if (touch_num > ts->max_touch_num)
return -EPROTO;
if((data[0]&0x80)==0)//坐标未就绪，数据无效
return -EPROTO;
if (touch_num > 1) {
data += 1 + GOODIX_CONTACT_SIZE;
error = goodix_i2c_read(ts->client,
GOODIX_READ_COOR_ADDR +
1 + GOODIX_CONTACT_SIZE,
data,
GOODIX_CONTACT_SIZE *
(touch_num - 1));
if (error)
return error;
}
return touch_num;
}
usleep_range(1000, 2000); /* Poll every 1 - 2 ms */
} while (time_before(jiffies, max_timeout));
/*
* The Goodix panel will send spurious interrupts after a
* 'finger up' event, which will always cause a timeout.
*/
return 0;
}
static void goodix_ts_report_touch(struct goodix_ts_data *ts, u8 *coor_data)
{
int id = coor_data[0] & 0x0F;
int input_x = get_unaligned_le16(&coor_data[1]);
int input_y = get_unaligned_le16(&coor_data[3]);
int input_w = get_unaligned_le16(&coor_data[5]);
/* Inversions have to happen before axis swapping */
if (ts->inverted_x)
input_x = ts->abs_x_max - input_x;
if (ts->inverted_y)
input_y = ts->abs_y_max - input_y;
if (ts->swapped_x_y)
swap(input_x, input_y);
input_mt_slot(ts->input_dev, id);
input_mt_report_slot_state(ts->input_dev, MT_TOOL_FINGER, true);
input_report_abs(ts->input_dev, ABS_MT_POSITION_X, input_x);
input_report_abs(ts->input_dev, ABS_MT_POSITION_Y, input_y);
input_report_abs(ts->input_dev, ABS_MT_TOUCH_MAJOR, input_w);
input_report_abs(ts->input_dev, ABS_MT_WIDTH_MAJOR, input_w);
}
/**
* goodix_process_events - Process incoming events
*
* @ts: our goodix_ts_data pointer
*
* Called when the IRQ is triggered. Read the current device state, and push
* the input events to the user space.
*/
static void goodix_process_events(struct goodix_ts_data *ts)
{
u8 point_data[1 + GOODIX_CONTACT_SIZE * GOODIX_MAX_CONTACTS];
int touch_num;
int i;
touch_num = goodix_ts_read_input_report(ts, point_data);
if (touch_num < 0)
return;
/*
* Bit 4 of the first byte reports the status of the capacitive
* Windows/Home button.
*/
input_report_key(ts->input_dev, KEY_LEFTMETA, point_data[0] & BIT(4));
for (i = 0; i < touch_num; i++)
goodix_ts_report_touch(ts,
&point_data[1 + GOODIX_CONTACT_SIZE * i]);
input_mt_sync_frame(ts->input_dev);
input_sync(ts->input_dev);
}
/**
* goodix_ts_irq_handler - The IRQ handler
*
* @irq: interrupt number.
* @dev_id: private data pointer.
*/
static irqreturn_t goodix_ts_irq_handler(int irq, void *dev_id)
{
struct goodix_ts_data *ts = dev_id;
goodix_process_events(ts);
if (goodix_i2c_write_u8(ts->client, GOODIX_READ_COOR_ADDR, 0) < 0)
dev_err(&ts->client->dev, "I2C write end_cmd error\n");
return IRQ_HANDLED;
}
static void goodix_free_irq(struct goodix_ts_data *ts)
{
devm_free_irq(&ts->client->dev, ts->client->irq, ts);
}
static int goodix_request_irq(struct goodix_ts_data *ts)
{
return devm_request_threaded_irq(&ts->client->dev, ts->client->irq,
NULL, goodix_ts_irq_handler,
ts->irq_flags, ts->client->name, ts);
}
/**
* goodix_check_cfg - Checks if config fw is valid
*
* @ts: goodix_ts_data pointer
* @cfg: firmware config data
*/
static int goodix_check_cfg(struct goodix_ts_data *ts,
const struct firmware *cfg)
{
int i, raw_cfg_len;
u8 check_sum = 0;
if (cfg->size > GOODIX_CONFIG_MAX_LENGTH) {
dev_err(&ts->client->dev,
"The length of the config fw is not correct");
return -EINVAL;
}
raw_cfg_len = cfg->size - 2;
for (i = 0; i < raw_cfg_len; i++)
check_sum += cfg->data[i];
check_sum = (~check_sum) + 1;
if (check_sum != cfg->data[raw_cfg_len]) {
dev_err(&ts->client->dev,
"The checksum of the config fw is not correct");
return -EINVAL;
}
if (cfg->data[raw_cfg_len + 1] != 1) {
dev_err(&ts->client->dev,
"Config fw must have Config_Fresh register set");
return -EINVAL;
}
return 0;
}
/**
* goodix_send_cfg - Write fw config to device
*
* @ts: goodix_ts_data pointer
* @cfg: config firmware to write to device
*/
static int goodix_send_cfg(struct goodix_ts_data *ts,
const struct firmware *cfg)
{
int error;
error = goodix_check_cfg(ts, cfg);
if (error)
return error;
error = goodix_i2c_write(ts->client, GOODIX_REG_CONFIG_DATA, cfg->data,
cfg->size);
if (error) {
dev_err(&ts->client->dev, "Failed to write config data: %d",
error);
return error;
}
dev_dbg(&ts->client->dev, "Config sent successfully.");
/* Let the firmware reconfigure itself, so sleep for 10ms */
usleep_range(10000, 11000);
return 0;
}
static int goodix_int_sync(struct goodix_ts_data *ts)
{
int error;
error = gpiod_direction_output(ts->gpiod_int, 0);
if (error)
return error;
msleep(50); /* T5: 50ms */
error = gpiod_direction_input(ts->gpiod_int);
if (error)
return error;
return 0;
}
/**
* goodix_reset - Reset device during power on
*
* @ts: goodix_ts_data pointer
*/
static int goodix_reset(struct goodix_ts_data *ts)
{
int error;
/* begin select I2C slave addr */
error = gpiod_direction_output(ts->gpiod_rst, 0);
if (error)
return error;
msleep(15);
/* HIGH: 0x28/0x29, LOW: 0xBA/0xBB */
error = gpiod_direction_output(ts->gpiod_int, ts->client->addr == 0x14);
if (error)
{
printk("[log]gpiod_direction_output int 1 err\r\n");
return error;
}
usleep_range(100, 2000); /* T3: > 100us */
error = gpiod_direction_output(ts->gpiod_rst, 1);
if (error)
{
printk("[log]gpiod_direction_output rst 1 err\r\n");
return error;
}
usleep_range(6000, 10000); /* T4: > 5ms */
/* end select I2C slave addr */
//error = gpiod_direction_input(ts->gpiod_rst);
//if (error)
// return error;
//msleep(50); /* T5: 50ms */
error = goodix_int_sync(ts);
if (error)
return error;
return 0;
}
/**
* goodix_get_gpio_config - Get GPIO config from ACPI/DT
*
* @ts: goodix_ts_data pointer
*/
static int goodix_get_gpio_config(struct goodix_ts_data *ts)
{
int error;
struct device *dev;
struct gpio_desc *gpiod;
if (!ts->client)
return -EINVAL;
dev = &ts->client->dev;
/* Get the interrupt GPIO pin number */
gpiod = devm_gpiod_get_optional(dev, GOODIX_GPIO_INT_NAME, GPIOD_IN);
if (IS_ERR(gpiod)) {
error = PTR_ERR(gpiod);
if (error != -EPROBE_DEFER)
dev_dbg(dev, "Failed to get %s GPIO: %d\n",
GOODIX_GPIO_INT_NAME, error);
return error;
}
ts->gpiod_int = gpiod;
/* Get the reset line GPIO pin number */
gpiod = devm_gpiod_get_optional(dev, GOODIX_GPIO_RST_NAME, GPIOD_IN);
if (IS_ERR(gpiod)) {
error = PTR_ERR(gpiod);
if (error != -EPROBE_DEFER)
dev_dbg(dev, "Failed to get %s GPIO: %d\n",
GOODIX_GPIO_RST_NAME, error);
return error;
}
ts->gpiod_rst = gpiod;
return 0;
}
/**
* goodix_read_config - Read the embedded configuration of the panel
*
* @ts: our goodix_ts_data pointer
*
* Must be called during probe
*/
static void goodix_read_config(struct goodix_ts_data *ts)
{
u8 config[GOODIX_CONFIG_MAX_LENGTH];
int error;
error = goodix_i2c_read(ts->client, GOODIX_REG_CONFIG_DATA,
config, ts->cfg_len);
if (error) {
dev_warn(&ts->client->dev,
"Error reading config (%d), using defaults\n",
error);
ts->abs_x_max = GOODIX_MAX_WIDTH;
ts->abs_y_max = GOODIX_MAX_HEIGHT;
if (ts->swapped_x_y)
swap(ts->abs_x_max, ts->abs_y_max);
ts->int_trigger_type = GOODIX_INT_TRIGGER;
ts->max_touch_num = GOODIX_MAX_CONTACTS;
return;
}
ts->abs_x_max = get_unaligned_le16(&config[RESOLUTION_LOC]);
ts->abs_y_max = get_unaligned_le16(&config[RESOLUTION_LOC + 2]);
if (ts->swapped_x_y)
swap(ts->abs_x_max, ts->abs_y_max);
ts->int_trigger_type = config[TRIGGER_LOC] & 0x03;
ts->max_touch_num = config[MAX_CONTACTS_LOC] & 0x0f;
if (!ts->abs_x_max || !ts->abs_y_max || !ts->max_touch_num) {
dev_err(&ts->client->dev,
"Invalid config, using defaults\n");
ts->abs_x_max = GOODIX_MAX_WIDTH;
ts->abs_y_max = GOODIX_MAX_HEIGHT;
if (ts->swapped_x_y)
swap(ts->abs_x_max, ts->abs_y_max);
ts->max_touch_num = GOODIX_MAX_CONTACTS;
}
if (dmi_check_system(rotated_screen)) {
ts->inverted_x = true;
ts->inverted_y = true;
dev_dbg(&ts->client->dev,
"Applying '180 degrees rotated screen' quirk\n");
}
}
/**
* goodix_read_version - Read goodix touchscreen version
*
* @ts: our goodix_ts_data pointer
*/
static int goodix_read_version(struct goodix_ts_data *ts)
{
int error;
u8 buf[6];
char id_str[5];
error = goodix_i2c_read(ts->client, GOODIX_REG_ID, buf, sizeof(buf));
if (error) {
dev_err(&ts->client->dev, "read version failed: %d\n", error);
return error;
}
memcpy(id_str, buf, 4);
id_str[4] = 0;
if (kstrtou16(id_str, 10, &ts->id))
ts->id = 0x1001;
ts->version = get_unaligned_le16(&buf[4]);
dev_info(&ts->client->dev, "ID %d, version: %04x\n", ts->id,
ts->version);
return 0;
}
/**
* goodix_i2c_test - I2C test function to check if the device answers.
*
* @client: the i2c client
*/
static int goodix_i2c_test(struct i2c_client *client)
{
int retry = 0;
int error;
u8 test;
while (retry++ < 2) {
error = goodix_i2c_read(client, GOODIX_REG_CONFIG_DATA,
&test, 1);
if (!error)
return 0;
dev_err(&client->dev, "i2c test failed attempt %d: %d\n",
retry, error);
msleep(20);
}
return error;
}
/**
* goodix_request_input_dev - Allocate, populate and register the input device
*
* @ts: our goodix_ts_data pointer
*
* Must be called during probe
*/
static int goodix_request_input_dev(struct goodix_ts_data *ts)
{
int error;
ts->input_dev = devm_input_allocate_device(&ts->client->dev);
if (!ts->input_dev) {
dev_err(&ts->client->dev, "Failed to allocate input device.");
return -ENOMEM;
}
input_set_abs_params(ts->input_dev, ABS_MT_POSITION_X,
0, ts->abs_x_max, 0, 0);
input_set_abs_params(ts->input_dev, ABS_MT_POSITION_Y,
0, ts->abs_y_max, 0, 0);
input_set_abs_params(ts->input_dev, ABS_MT_WIDTH_MAJOR, 0, 255, 0, 0);
input_set_abs_params(ts->input_dev, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0);
input_mt_init_slots(ts->input_dev, ts->max_touch_num,
INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
ts->input_dev->name = "Goodix Capacitive TouchScreen";
ts->input_dev->phys = "input/ts";
ts->input_dev->id.bustype = BUS_I2C;
ts->input_dev->id.vendor = 0x0416;
ts->input_dev->id.product = ts->id;
ts->input_dev->id.version = ts->version;
/* Capacitive Windows/Home button on some devices */
input_set_capability(ts->input_dev, EV_KEY, KEY_LEFTMETA);
error = input_register_device(ts->input_dev);
if (error) {
dev_err(&ts->client->dev,
"Failed to register input device: %d", error);
return error;
}
return 0;
}
/**
* goodix_configure_dev - Finish device initialization
*
* @ts: our goodix_ts_data pointer
*
* Must be called from probe to finish initialization of the device.
* Contains the common initialization code for both devices that
* declare gpio pins and devices that do not. It is either called
* directly from probe or from request_firmware_wait callback.
*/
static int goodix_configure_dev(struct goodix_ts_data *ts)
{
int error;
ts->swapped_x_y = device_property_read_bool(&ts->client->dev,
"touchscreen-swapped-x-y");
ts->inverted_x = device_property_read_bool(&ts->client->dev,
"touchscreen-inverted-x");
ts->inverted_y = device_property_read_bool(&ts->client->dev,
"touchscreen-inverted-y");
goodix_read_config(ts);
error = goodix_request_input_dev(ts);
if (error)
return error;
ts->irq_flags = goodix_irq_flags[ts->int_trigger_type] | IRQF_ONESHOT;
error = goodix_request_irq(ts);
if (error) {
dev_err(&ts->client->dev, "request IRQ failed: %d\n", error);
return error;
}
return 0;
}
/**
* goodix_config_cb - Callback to finish device init
*
* @ts: our goodix_ts_data pointer
*
* request_firmware_wait callback that finishes
* initialization of the device.
*/
static void goodix_config_cb(const struct firmware *cfg, void *ctx)
{
struct goodix_ts_data *ts = ctx;
int error;
if (cfg) {
/* send device configuration to the firmware */
error = goodix_send_cfg(ts, cfg);
if (error)
goto err_release_cfg;
}
goodix_configure_dev(ts);
err_release_cfg:
release_firmware(cfg);
complete_all(&ts->firmware_loading_complete);
}
static int goodix_ts_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct goodix_ts_data *ts;
int error;
dev_dbg(&client->dev, "I2C Address: 0x%02x\n", client->addr);
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
dev_err(&client->dev, "I2C check functionality failed.\n");
return -ENXIO;
}
ts = devm_kzalloc(&client->dev, sizeof(*ts), GFP_KERNEL);
if (!ts)
return -ENOMEM;
ts->client = client;
i2c_set_clientdata(client, ts);
init_completion(&ts->firmware_loading_complete);
error = goodix_get_gpio_config(ts);
if (error)
{
printk("[log]goodix_get_gpio_config\r\n");
return error;
}
if (ts->gpiod_int && ts->gpiod_rst) {
/* reset the controller */
error = goodix_reset(ts);
if (error) {
dev_err(&client->dev, "Controller reset failed.\n");
return error;
}
}
error = goodix_i2c_test(client);
if (error) {
printk("[log]I2C communication failure: %d\n",error);
dev_err(&client->dev, "I2C communication failure: %d\n", error);
return error;
}
error = goodix_read_version(ts);
if (error) {
printk("[log]Read version failed.\n");
dev_err(&client->dev, "Read version failed.\n");
return error;
}
ts->cfg_len = goodix_get_cfg_len(ts->id);
if (ts->gpiod_int && ts->gpiod_rst) {
/* update device config */
ts->cfg_name = devm_kasprintf(&client->dev, GFP_KERNEL,
"goodix_%d_cfg.bin", ts->id);
if (!ts->cfg_name)
return -ENOMEM;
error = request_firmware_nowait(THIS_MODULE, true, ts->cfg_name,
&client->dev, GFP_KERNEL, ts,
goodix_config_cb);
if (error) {
dev_err(&client->dev,
"Failed to invoke firmware loader: %d\n",
error);
return error;
}
return 0;
} else {
error = goodix_configure_dev(ts);
if (error)
return error;
}
return 0;
}
static int goodix_ts_remove(struct i2c_client *client)
{
struct goodix_ts_data *ts = i2c_get_clientdata(client);
if (ts->gpiod_int && ts->gpiod_rst)
wait_for_completion(&ts->firmware_loading_complete);
return 0;
}
static int __maybe_unused goodix_suspend(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct goodix_ts_data *ts = i2c_get_clientdata(client);
int error;
/* We need gpio pins to suspend/resume */
if (!ts->gpiod_int || !ts->gpiod_rst) {
disable_irq(client->irq);
return 0;
}
wait_for_completion(&ts->firmware_loading_complete);
/* Free IRQ as IRQ pin is used as output in the suspend sequence */
goodix_free_irq(ts);
/* Output LOW on the INT pin for 5 ms */
error = gpiod_direction_output(ts->gpiod_int, 0);
if (error) {
goodix_request_irq(ts);
return error;
}
usleep_range(5000, 6000);
error = goodix_i2c_write_u8(ts->client, GOODIX_REG_COMMAND,
GOODIX_CMD_SCREEN_OFF);
if (error) {
dev_err(&ts->client->dev, "Screen off command failed\n");
gpiod_direction_input(ts->gpiod_int);
goodix_request_irq(ts);
return -EAGAIN;
}
/*
* The datasheet specifies that the interval between sending screen-off
* command and wake-up should be longer than 58 ms. To avoid waking up
* sooner, delay 58ms here.
*/
msleep(58);
return 0;
}
static int __maybe_unused goodix_resume(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct goodix_ts_data *ts = i2c_get_clientdata(client);
int error;
if (!ts->gpiod_int || !ts->gpiod_rst) {
enable_irq(client->irq);
return 0;
}
/*
* Exit sleep mode by outputting HIGH level to INT pin
* for 2ms~5ms.
*/
error = gpiod_direction_output(ts->gpiod_int, 1);
if (error)
return error;
usleep_range(2000, 5000);
error = goodix_int_sync(ts);
if (error)
return error;
error = goodix_request_irq(ts);
if (error)
return error;
return 0;
}
static SIMPLE_DEV_PM_OPS(goodix_pm_ops, goodix_suspend, goodix_resume);
static const struct i2c_device_id goodix_ts_id[] = {
{ "GDIX1001:00", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, goodix_ts_id);
#ifdef CONFIG_ACPI
static const struct acpi_device_id goodix_acpi_match[] = {
{ "GDIX1001", 0 },
{ "GDIX1002", 0 },
{ }
};
MODULE_DEVICE_TABLE(acpi, goodix_acpi_match);
#endif
#ifdef CONFIG_OF
static const struct of_device_id goodix_of_match[] = {
{ .compatible = "goodix,gt911" },
{ .compatible = "goodix,gt9110" },
{ .compatible = "goodix,gt912" },
{ .compatible = "goodix,gt927" },
{ .compatible = "goodix,gt9271" },
{ .compatible = "goodix,gt928" },
{ .compatible = "goodix,gt967" },
{ }
};
MODULE_DEVICE_TABLE(of, goodix_of_match);
#endif
static struct i2c_driver goodix_ts_driver = {
.probe = goodix_ts_probe,
.remove = goodix_ts_remove,
.id_table = goodix_ts_id,
.driver = {
.name = "Goodix-TS",
.acpi_match_table = ACPI_PTR(goodix_acpi_match),
.of_match_table = of_match_ptr(goodix_of_match),
.pm = &goodix_pm_ops,
},
};
module_i2c_driver(goodix_ts_driver);
MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
MODULE_AUTHOR("Bastien Nocera <hadess@hadess.net>");
MODULE_DESCRIPTION("Goodix touchscreen driver");
MODULE_LICENSE("GPL v2");
9.13.2、在内核配置中添加CONFIG项
(1)定义一个宏名，譬如CONFIG_TOUCHSCREEN_GOODIX
(2)在代码中使用宏来条件编译
(3)在Makefile中使用宏来条件配置
obj-$(CONFIG_TOUCHSCREEN_GOODIX) += goodix.o
(4)在Kconfig项目中添加宏的配置项
config TOUCHSCREEN_GOODIX
tristate "Goodix I2C touchscreen"
depends on I2C
depends on GPIOLIB || COMPILE_TEST
help
Say Y here if you have the Goodix touchscreen (such as one
installed in Onda v975w tablets) connected to your
system. It also supports 5-finger chip models, which can be
found on ARM tablets, like Wexler TAB7200 and MSI Primo73.
If unsure, say N.
To compile this driver as a module, choose M here: the
module will be called goodix.
(5)make menuconfig并选择Y或者N
更多推荐
1
0- 0
已为社区贡献1条内容
所有评论(0)